{I’m not new here, for some reason my old account was deleted }
So This year for my control system, I am putting it in a box for protection. The only outside interface will be for the motors.
I am trying to find a connector that will be able to handle 28 or so motor-gauge wire. I would prefer one connector, but if it requires up to three that would be fine.
Anyone have any suggestions or recommendations for connectors that would accomplish this?
I suggest you keep the motor wires separated by motor, so if you have to replace or troubleshoot a motor, it will be a lot easier.
PA45 Anderson Powerpole connectors work well, you can pair them, use different colors, and they are pretty reliable.
I’d start by looking at the Delphi Metri-pack series of connectors. Be careful though as you will find a number of connectors that have terminals that will accept up to 12 ga wire but are not rated to carry the full current capacity of a 12ga wire. They are only set up to accept that large gauge wire to prevent voltage drop. Also a given connector has a maximum total amperage capacity that again is not based on the size of the wire that terminals that will fit it are capable of handling. So you may find that 28 position connector that will accept terminals that can handle 40 amps each but not 400 amps that would result from 5 pairs of terminals carrying 40 amps.
Checkout the Anderson Power Pole series. the PP45’s can handle up to 45A, so they’re great for our applications. It’s a single connector for each lead, but they interlock together to form larger connectors very easily. They also give you good polarity protection when you lock two or more together, as there’s only 1 way to plug them in (like the Anderson connector we use for the battery).
If you decide to go that route, I highly recommend getting a proper crimper for them, like the one available here: http://www.westmountainradio.com/product_info.php?products_id=PWRcrimp
In previous years, we used the Anderson Powerpole connectors for motor power and DB37 or DB25 (multiple of them if necessary) for signals. You don’t really want power wires to go in the same bundle with the signal wires anyway. They might inject noise to your signal wires.
Note those are only rated for 45A when used with 10 ga wire in a single configuration. With a 12ga wire they drop to 35A in a single configuration. Connect them in a multiple configuration and with the 10ga wire the rating drops to just over 30A per terminal, with 12ga it is just over 20A per terminal for loads occurring for more than ~1 minute.
http://andersonpower.com/files.php?file=DS-PP45(6).pdf
As I noted above you need to consider not only the size of wire it will accept, but the ampacity of the terminal and the ampacity of the connector as a system.
Of course that doesn’t mean that you can’t get away with it as we all do with the legal battery connector which is only rated at 60 amps when fitted with 6ga wire for the duration of a standard FRC match. Yet it is “protected” with a circuit breaker rated at twice that.
The motor wires are 14 gage, aren’t they? yet teams have been “getting away” with using the PowerPole connectors for them for years. I haven’t heard of any of them melting.
Most ratings are very conservative for what we’re doing, what with the very short life expectancy we require of a competition robot.
I never even thought about using those. that would be awesome because they can be attached to the side of my case easily… Where would I go to order them?
I cant find any called a PA45 on their website… typo?
PP45 is the correct series.
http://www.powerwerx.com/anderson-powerpoles/housings-contacts/
The crimping tool that they sell in very good. We had some trouble last year getting the pins seated in the housing. Using their tool solved the problem.
http://www.powerwerx.com/crimping-tools/tricrimp-crimping-powerpole-contacts.html
IMO, the only real acceptable application (for FRC purposes) of 28AWG wire is a circuit board - I wouldn’t really be comfortable with it in any other situation. If you must, though, screw terminals may also work for you.
on our 2009 bot we melted the Anderson powerpoles on our intake roller it got jammed and the powerpoles melted and dripped down our frame
i would definitely recommend deans convectors they are much better
Please remember that the current ratings on the Anderson connectors are the continuous duty ratings. These can be derated when used in an under three minute match. We have used the 45 amp connectors for at least 10 years now and have never had one fail. We use #10 for most applications involving high current motors. While it is difficult to insert #10, I spread the contact a little to help. Using the APP crimper (we got ours from West Mountain Radio) the contact is returned to normal and makes a great connection. As extra insurance, we add a little solder just to be sure.
The Anderson connectors can be stacked into multiple contacts that are also polarized. We have used up to sixteen contacts in one connector bundle in the past.
Oh thanks then!
I did screw terminals last year, only problem is that there isnt really a quick way to disconnect the control box.
Were you using the 45A contacts? Which motor were you using?
Read the data sheet I provided the link too. 45A rating is the continuous duty, which for this connector is considered more than 1 minute, only when they are in a single configuration with 10ga wire.
Stack them together and the continuous duty rating drops way down.
I realize many teams “have gotten away with it” however one of the concepts of first is to encourage good, safe design practice. Using a connector rated for ~30A in a circuit that uses a 40A circuit protection device is not good, nor safe design.
I think that’s debatable…
Defining the requirements well is part of the design process. One of the requirements is that the robot last thru several 2:15 minute matches. That’s quite different than most commercial products.
Lets also keep in mind that most robots won’t be sending 30+ A to a motor for more than a minute. Your CIM motors will get that high when you’re starting from a stop, or when you’re pushing against something, but those are typically relatively short moments. Most of the match, your drive train will be pulling somewhere in the teens, if not lower. As for the other motors… even the FP we had powering our elevator last year wasn’t pulling 30 A throughout the match… and it was either stalled or moving pretty much the entire time (and we had some serious binding issues in the elevator).